1. Field of the Invention
The present application relates to devices and methods for frameless image-guided biopsy and/or therapeutic intervention. In particular, the present application relates to devices and methods for frameless image-guided stereotactic, CT, and/or MRI system biopsy, therapeutic intervention and/or drug delivery for tumors using stereoscopic imaging, laser guidance, and/or infrared-based positioning and tracking of patients, utilizing, for example, a six-dimensional (6D) robotic couch system.
2. Description of the Related Art
Medical treatment of a patient often includes a medical professional obtaining a biopsy sample from the patient to evaluate the condition of the patient and plan an appropriate treatment. For example, a surgeon may need to collect a sample to perform a biopsy of a brain tumor prior to further treatment or surgery. Traditional systems and methods for collection of a biopsy sample can be complicated, cumbersome, and may be overly invasive to the patient.
A rigid frame-based stereotactic biopsy system is considered the industry standard for evaluation of histological specimens from targets within the brain. The frame-based system requires attachment of a frame to the skull of a patient to assist the surgeon in locating and collecting a sample from a specific targeted location within the brain. The patient requires anesthesia during the procedure. The frame is typically attached to the patient by invasively inserting four screws into the skull. This frame-based method provides the neurosurgeon with a generally safe (mortality <1%, morbidity 3-4%) and effective (diagnostic yield >95%) means for biopsy retrieval. The frame-based system has advantages over some other biopsy procedures. For example, the frame-based system has provided advantages for patient outcomes compared with freehand (CT-directed) burr-hole biopsy (mortality >5%, morbidity 15%, diagnostic yield 85%).
However, frame-based head fixation can be painful and the head movement limitation can be intolerable to many patients. Furthermore, there is risk of epidural hematoma, cranial fracture, and cerebrospinal fluid (CSF) leak following the application of head pins, and laceration of the scalp with patient movement especially in young children. From the surgeon's perspective, rigid head fixation can also be problematic since the head pins are bulky and limit intraoperative flexibility as well as free movement of surgical instruments. If the patient's head moves relative to a reference arc, the accuracy of the system is greatly reduced, potentially compromising successful execution of the procedure. Unlike surgery, the risks of image-guided frameless biopsy are infinitely less.
Currently, most extra-cranial biopsies are done using CT-guided biopsy, such as, for example, CT-guided spinal biopsy (CTGSB). Recent studies analyzed the accuracy of a CTGSB of osseous spinal lesions in patients with known or suspected underlying malignancy in reference to major variables such as the radiographic appearance of the biopsied lesion and its location within the spinal column. The results showed an overall diagnostic accuracy of CTGSB to be 89%, with a false-negative rate of 11%. Biopsy of lytic lesions yielded an accurate diagnosis in 93% (220 of 236). Despite technical challenges inherent to biopsy of sclerotic lesions, diagnostic accuracy was 76% (63 of 83) and, significantly, 24% (20 of 83) of the results in sclerotic lesions were falsely negative.
CT Guided biopsy can be challenging at times because the patient has to be moved out of the CT gantry to place the needle, thus lowering the precision and causing the high false-negative rate of 11% to 24% for lytic and sclerotic lesions, respectively, and low diagnostic accuracy of 76%. Furthermore, current systems typically do not utilize image fusion that can help delineate the tumor by using high soft tissue contrast imaging provided by MRI, or high metabolic tumor activities information that can be provided by PET scans. Another disadvantage of the CT-guidance is high ionizing radiation exposure to the patient or the interventional radiologist since the patient has to be scanned before, during, and maybe after the needle placement.